Rock drill



J. C. CURTIS Sept; 7, 1937.

ROCK DRILL Filed April 25, 1936 Patented Sept. 7, 1937 ROCK DRILL Garfield Heights, Ohio, assignor `lohn C. Curtis,

PATENT oFFicli to The Cleveland Rock Drill Company, Cleveland, Ohio, acorporation of Ohio Application April 23, 193s, serian No. 76,001 ,s claims. (C1. 1er- 7)i This invention relates broadlyA to rock drills,

but more particularly to a rotation mechanism` for fluid actuated type. j

One object ofthis invention is `to produce an improved rotation mechanism' for rock drills, the

rockdrills of the percussive mechanism having "a reduced number of parts and affording' a simple construction which is strongfdurable and ellicient.

Otherobjects `offthis invention will be apparent from the following detailed description wherein similar characters of reference designate corresponding parts and wherein:

Fig. 1 is an elevational sectional `View of a rock drill having the'inventionapplied thereto.

` Figs. 2 and 3 are .views similar to Fig.` 1 illustrating some of theparts in different position.

Fig. 4 is an enlarged cross sectional view taken in a plane indicated" by line 4-4 in Fig. 1.

Fig. 5 is an enlarged cross sectional View taken in a plane indicated'by line 5`5 in Fig. 1.

Fig. 6 is a portion of an elevational sectional View, illustrating details of construction.

Referring to the drawing,` I0 represents the cylinder of a rock drill having a piston II reciprocable therein for delivering blows to a tool implement (not shown); `The upper end of the cylinder I is formed with a relatively7 deep counterbore I2 having disposed therein aivalve cap 30 I3, valve casing I4, ring I5`and bearing plate I6.

These four parts are locked against rotation relative to the cylinder by'means of a dowel pin II, and against relative longitudinal movement by a back head I8 rigidly secured to the cylinder I0 by the usual bolts or side rods (not shown). Located within the valve cap I3 and valve casing I4, there is a valve `bushing I9 having a valve slidable thereon. This valve is formed with anl annular flange 2| extending into anannular groove-22 provided within the valve cap` I3 and `valve casing I4 adjacent two annular valve seats 23 and 24 with which the valve flange 2| is capable of alternative engagement.4 The upper portion of the valve 20 is formed with a counterbore, the bottom 25 thereof constituting a valve kicking area on `which motive fluid may be admitted from the` cylinder I0 through a kicker port 26, groove 21, and ports 28 provided `Within the valve bushing I9. Within the valve casing I4, above the annular groove 22, there is another annular groove29 capable of communication With the front end of .the cylinder I0 through aA port 30. I

The back head ,I8v is properly machined to rotatably receive a throttle valve 3l `formed with a" central bore 32 having motivefluid admitted therein, and aradial port 33 affording the communication of the bore 32 with a'port34 formed within theback head I8. `This' last port opens into an enlarged chamber 35 provided within the bearing plate or clutchl member I6, which chamber is i-n communication with thev annular groove 22 through a plurality of ports 36.

The clutch member I5 has a reduced portion 31 extending partway into the ring 15, and has its vend wall shaped in an annular ridge provided with radially disposed ratchet teeth 33. Slidably and rotatably mounted' within the ring I5 below the clutch member' 3l, therey is the cylindrical head 39of a stem 40. This head has its upper end wall also provided with radially disposed ratchet teeth 4I engageable with the teeth 38 of the clutch `member I6. The lower side 42 of the head 39 is provided witha relatively small annular shoulder 43 engageable with vthe" upper c end wall ofthe valve casing I4, and thereby af fording an' annular Vclearancelbetween the latter and the lower `wall 42 of the head 39.

The stem-4!) extends through the bushing I9 into the cylinder I0, where it is provided with helical splines `44 engageable with similar splines formed within the p-istonII.

Disposed on one side of the cylinder I0, there is a boss 45 having rotatable therein a cylindrical valve 46 which maybe rotated by a handle 41 formed integrally therewith. 'Ihis valve isI held against longitudinal movement by the back head I8 overlapping the same as at 48. To maintain the valve 46 against `accidental rotation, there is in the wall of the Cylinder Ill, a spring pressed plunger 49 which is constantly urged into detents formed under the :valve handle 4l. The valve 46 is provided with a central port 50, which is in constant communication with the rear end of the cylinder I0 through a port 5I. The valve port 50 is also capable of communica tion with the lower Wall of the clutch member I5 through a port 52 and radially disposed valve port V53. `Disposedat substantially right angles from the port 53, the peripheral wall of the Valve 46n is carved to form a longitudinal slot 54 af'- fording the communication of the portV 52 with a port 55 opening into the port 35. Directly below the valve port 53, the peripheral wall of the vValve is formed with another slot 56, Which'is capable offaffording the communication of two ports 51 and 58, the former leading into the annular groove 29', while the latter leads to the lower wall 42 lol" the head 39. Diametrically opposed to the port 58-y the cylinderfboss 45 is provided witha CTI port 59 leading from the valve 46 to the atmosphere. The communication of this last port with the port 58 may be established through a partly annular groove 60 formed on the valve 46.

Leading from the annular groove 22 into the rear end of the cylinder I0, there is a plurality of ports 60, and from the cylinder to the atmosphere, there is an exhaust port 6|.

The operation of the mechanism is as follows: Assuming that the throttle valve 3| and cylindrical valve 46 are positioned as shown in Fig. 1, the motive uid from the throttle valve bore 32 will ow into the enlarged chamber 35 through the ports 33 and 34. From this last chamber, it will be admitted into, the annular groove 22 via the ports 36, thus acting on the front end wall of the valve to maintain the same in the position shown in Fig. 1. From the annular groove 22, the motive fluid is.A free to i'low into the rear end of the cylinder I0 through the ports 60, thus acting on the piston II to drive the latter forwardly for delivering a blow to the tool implement mounted within the front end of the machine. With the valve 46 positioned as shown in Fig.. 1, motive fluid from the rear end of the cylinder is also admitted through the port 5|-, valve ports 50 and 53, and port 52, between the clutch member I5' and the head 39 of the stem 4I), thus maintaining the teeth 4| of the latter out of engagement with the teeth 38 of the clutch member I6, and thereby permitting a free rotation of the stem 40. During the downward movement of the piston I, the latter instead of rotating due to its interengagement with the helical splines 44, will cause a partial revolution lof the stem 40.

When the piston II uncovers the kick port 26, motive iluid will flow from inside of the cylinder I0 through the p ort 26, annular groove 21, and ports 28, to the kicking area 25 of the valve 2D, thus tending to shift the valve forwardly. Subsequently, the piston II uncovering the exhaust port 6| will allow the motive fluid within the rear-end of the cylinder to escape to the atmosphere, thus causing a drop of pressure on the forward end wall of the valve, and causing the latter to assume the position shown, in Fig. 2. Simultaneously the motive fluid previously admitted between the clutch member I6 and head 39 is also free to exhaust via the ports 52, 53, 50, 5I, and exhaust port 6|.

With the valve 20 in the position shown in Fig. 2, motive uid from the annular groove 22 will flow around the valve inthe annular groove 29, to act on the end of the valve 20 for maintaining it in its forward position. From the groove 29, the motive duid will also flow into the front end of the cylinder IU through the port 30. In this instance, motive iiuid will also flow to the front end wall 42 of the stem head 39 via the port 51, slot 56 and port 58, thus acting on the head 39 to drive and maintain it in the position shown in Fig. 2, that is, with its teeth 4I in operative engagement with the teeth 38 of the stationary clutch member I6 for locking the stem 40 against rotation. The motive fluid admitted into the front end of the cylinder IIIl through the port 30 and acting on the piston AI I, will drive the latter rearwardly. Due to the interengagement of the piston with the helical splines 44 of the now stationary stem 40, the former during its rearward movement will be forced to rotate, thus imparting rotation to the tool implement to move it in a new position preparatory to the delivery of a subsequent blow by the piston II.

During the rearward travel of the piston II, the latter will uncover the exhaust port 6I, thus allowing the motive fluid admitted into the front end of the cylinder to escape to the atmosphere, and causing a drop of pressure of the motive fluid admitted into the annular groove 29. Toward the end of the rearward travel of the piston II,

the motive fluid remaining within the rear end of the cylinder will be compressed by the piston and will act on the forward end wall of the valve 29. through the ports 69 to shift the valve into the position shown in Fig. 1. In this instance, the motive fluid previously admitted into the annular groove 29 is cut off to the valve 20 engaging the valve seat 24, thus allowing the motive iluid previously admitted on the lower end wall 42 of the stem head 39 to escape therefrom via the port 58, slot 56, port 51, annular groove 29 and port 30, andthereby completing the cycle of operation.

When it is desired to use the machine without imparting rotation to the tool implement, the cylindrical valve 46 may be positioned as shown in Fig. 3. In thisinstance, it will be noted that the lower end wall 42 of the stem head 39 is constantly in communication with the atmosphere through the port 58, valve groove and port 59. Simultaneously, motive fluid from the inlet port 36 is constantly admitted between the clutch member I6 and head 39, through the port 55, valve slot 54 and port 52, thus constantly acting on the head 39 'of the stem 40 for maintaining the teeth 4I of the former out of engagement with the teeth 38 of the clutch member I6, and thereby allowing the riiled stem 40 to rotate irrespectively of the position of the valve 20.

Although the foregoing description is necessarily of a detailed character in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or conning and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

l. In a uid actuated rock drill, the combination of a housing having a piston reciprocable therein, a longitudinally and rotatably movable rifle bar in interlocking engagement with said piston, opposed actuating areas on said bar one being larger than the other, a valve automatically operable for controlling the admission of the motive fluid into said housing for effecting the reciprocation of said piston, stationary means with which said bar is engageable for locking the same against rotation, means including passages for alternatively admitting and exhausting motive iluid to and from the actuating areas of said bar for longitudinally actuating the same in time relation with the reciprocation of said piston into engagement or disengagement with said stationary means for preventing or permitting the rotation of the bar, and a valve controlling said passages movable into one position for constantly admitting pressure fluid to the larger of said actuating areas for maintaining said bar out of engagement with said stationary means.

2. In a fluid actuated rock drill, the combination of a housing having a fluid actuated piston reciprocable therein, a reciprocable and rotatable rifle bar in interlocking engagement with said piston, opposed actuating areas on said bar, clutch means with which said bar is engageable for locking the same against rotation, and means for alternatively admitting and exhausting motive :Huid to and from said actuating areas for normally eifecting the reciprocation of said bar and the consequential engagement or disengagement of the latter with said clutch means and valve means operable for constantly admitting motive iiuid to one of said actuating areas and simultaneously exhausting the motive iiuid from the other of said actuating areas for maintaining said bar out of engagement with said clutch means irrespective of the reciprocation of said piston. e

3. In a fluid actuated rock drill, the combination of a housing having a fluid actuated piston reciprocable therein, a rotatable rifle bar in interlocking engagement with said piston, clutch means with which said riile bar is engageable for locking the same against rotation, opposed actuating areas on said bar means including passages ior alternatively admitting and exhausting motive iiuid to and from said actuating areas for normally eiecting the engagement and disengagement of said bar with said clutch means during the normal reciprocation of said piston, and means for selectively admitting motive iiuid to one of said actuating areas and exhausting the motive yfluid from the other of said actuating areas for maintaining said bar out of engagement with said clutch means irrespective of the reciprocation of said piston.

JOHN C. CURTIS. 

